A heat pump system (1) has such a configuration that a first utilization unit (4a) which performs hot water supply operation for heating a water medium and a second utilization unit (10a) which performs cooling/ heating operation for cooling or heating an air medium are connected with a common heat source unit (2) in a state where the hot water supply operation, cooling operation or heating operation cannot be selected individually, and the heat pump system can be operated by switching to a temperature control mode which is different from the switching state of a heat source side switching mechanism (23) as a temperature control mode which is commanded by a first utilization side controller (77a).